head, body {
    margin: 0;
    padding: 0;
}

/*a标签样式*/
a {

    text-decoration: none;
    text-decoration-color: black;
}

a:link {
    text-decoration: none;
    color: greenyellow;
}

a:visited {
    text-decoration: none;
    color: green;
}

/*button 样式*/
button {
    text-align: center;
    display: inline-block;
    position: relative;
    text-decoration: none;
    height: 30px;
    padding: 5px;
    background-color: #3478FF;
    color: white;
    border: none;
    width: 75px;
    -webkit-border-radius: 3px;
    -moz-border-radius: 3px;
    border-radius: 3px;
}

button:hover {
    width: 77px;
    height: 32px;
}


